protecting a signal net

[samabraham]

Why we should connect a shield to reference potential ?? Is it reference potential of the aggressor or victim??

 

[Ice-Tea]

Victim. If you have guard traces around a net that are not connected to anything, you actually jus t make a bad antenna that will not do much. You want to make that guard as low impedance as possible so that radiated energy that hits is quickly funneled away.!